Method for separating lead from a lead coated cable

ABSTRACT

APPARATUS AND A METHOD FOR SEPARATING A NUMBER OF DIFFERENT MATERIALS INITIALLY BOUND TOGETHER AND SEPARABLE FROM EACH OTHER BY THE APPLICATION OF HEAT. THE BOUND MATERIALS ARE MOVED INTO AND THROUGH A MASS OF MOLTEN LEAD ALONG A PREDETERMINED PATH AND FOR A TIME SUFFICIENT TO CAUSE THE SEPARATION OF THE MATERIALS FROM EACH OTHER. THE TEACHINGS OF THE INVENTION ARE ESPECIALLY ADAPTED FOR REMOVING THE COATING FROM ELONGATED LEAD-COATED MEMBERS, SUCH AS ELECTRICAL CABLES. THE MOLTEN LEAD IN THE LEAD MASS IS CIRCULATED TO PROVIDE A SUBSTANTIALLY UNIFORM TEMPERATURE DISTRIBUTION THROUGHOUT. ALSO, VIBRATORY MOTION IS IMPARTED TO THE MOLTEN LEAD TO FACILITATE THE SEPARATION OF THE MATERIALS FROM EACH OTHER. THE DROSS OF THE MOLTEN LEAD IN THE LEAD MASS IS KEPT FROM BEING MOVED OUT OF THE LEAD MASS WITH ONE OF THE MATERIALS AFTER THE MATERIALS HAVE BEEN SEPARATED FROM EACH OTHER.

S. J. M INTYRE Jan; 26,-- 19 71 ME'YIHODFOR SEPARATING LEAD FROM A LEAD COATED CABLE Filed'Ded. v. 1967 2 Sheets-Sheet 1 INVENTOR.

- STEPHEN J. MCINTYRE ATTORNEYS Jan. 26,1971 5. J. MCINTYRE 3,558,304

' METHOD FOR SEPARATING LEAD FROM A LEAD COATED CABLE Filed D90. 7. 1967 2 Sheets-Sheet 2 INVENTOR 80 STEPHEN J. McINTYRE so" 54' BY 80 r/// /z M v V ATTORNEYS United States Patent US. Cl. 75-63 6 Claims ABSTRACT OF THE DISCLOSURE Apparatus and a method for separating a number of different materials initially bound together and separable from each other by the application of heat. The bound materials are moved into and through a mass of molten lead along a predetermined path and for a time sufficient to cause the separation of the materials from each other. The teachings of the invention are especially adapted for removing the coating from elongated lead-coated members, such as electrical cables. The molten lead in the lead mass is circulated to provide a substantially uniform temperature distribution throughout. Also, vibratory motion is imparted to the molten lead to facilitate the separation of the materials from each other. The dross of the molten lead in the lead mass is kept from being moved out of the lead mass with one of the materials after the materials have been separated from each other.

This invention relates to improvements in the reclaiming of materials and, more particularly, to apparatus and method for separating a number of dissimilar materials from each other when the materials are initially bound together as a unit.

The apparatus and method of the present invention are directed to the separation of at least a pair of different materials initially forming a unitary body wherein the body is directed through a mass of molten lead along a predetermined path and for a time sufficient to cause one of the materials to disintegrate or otherwise separate from the other material due to the heat of the lead mass to which the one material responds. Following the separation, at least a first of the materials is directed to a location which is essentially spaced from the location at which the second material is disposed. In this way, the unitary body comprised of the materials is not only broken up into its various parts, but also the parts, i.e., the materials, themselves are segregated from each other.

While the present invention is applicable to the separation of a wide variety of different materials, it is especially adapted for use in removing the coating from leadcoated members, such as electrical cables. In the case of lead-coated electrical cables, it is desirable to reclaim the lead therefrom or it is deemed necessary to provide a different type of coating or insulation for the cable to permit it to more assuredly withstand the deleterious effects of the environment in which the cable is normally used. Since lead-coated electrical cables are extremely bulky and diflicult to handle unless cut into small pieces, a need has arisen to make the technique of removing the lead coating from the cables more economical as well as more practical. The present invention satisfies this need by eliminating a number of time-consuming steps which have been required in the past to achieve the above. The invention also substantially reduces the number of personnel required to handle the cable and minimizes the necessary equipment needed for this purpose. Thus, the cost of reclaiming lead from the cable or the expense of preparing the cable for a new coating is greatly reduced in comparison to costs involved in carrying out conventional techniques.

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Heretofore, the method generally used to separate the lead coating from cables of the above-mentioned type has included the step of initially cutting the coated cables into relatively short segments. The cutting of the cables is done at one location where cutting equipment is provided. These segments are then taken to a second location at which a blast furnace is disposed and the cable segments are directed into the blast furnace wherein the cables are subjected to intense heat to cause the lead coating on each segment to become molten. Wor-kmen near the blast furnace oftentimes must use probes to force the molten lead coating from the cable segments to assure positive separation. The lead coating melts and is collected in a receptacle below the furnace while the cable segments are left to cool to a temperature which allows the same to be handled. The cable segments are then moved to a third location where they are pressed together into a large mass. The pressed mass is then moved to a fourth location and melted, following which the melted material is poured into ingots and allowed to cool. The ingots are then moved to a fifth location, either for storage purposes or for the purposes of being formed back into cables.

The method and apparatus of the present invention avoid the problems encountered in'the practice of the above method by assuring that the lead coating can be readily separated from the cable while the cable itself remains intact and does not need to be cut into short lengths or segments. Thus, the cable can, as soon as the lead coating has been separated therefrom, be ready almost immediately for subsequent use or can be conveniently stored until the need for it again arises.

While the prior art methods and apparatus require high heat intensity and therefore the expenditure of considerable amount of fuel, the present invention only requires heat sufficient to keep a mass of lead in a molten condition. Thus, the present invention allows for minimum expenditure for fuel necessary to produce the heat.

Another disadvantage with the practice of conventional methods is that the separation of the lead coating from the cable is done in blast furnaces wherein combustion gases are heated to relatively high temperatures and directed against the lead-coated cable segments to effect the separation of the coating from the cable. The combustion gases must be exhausted and, in being exhausted, carry away a major portion of the lead that has been vaporized during the process of separating the lead coating from the cable segments. Tests have shown that this loss may be as high as 15% of the original volume of the lead.

The present invention avoids this problem by providing a mass of molten lead as the source of heat for separating the coating from the cable, the lead mass requiring only sufiicient heat to keep it molten. Thus, there is no need for extremely high melting temperatures as is required in blast furnaces and there is, as a result, a minimum or substantially no vaporization at the surface of the lead mass. Thus, there is negligible loss of lead to the atmosphere above the lead mass.

The apparatus of the present invention represents an improvement over the prior art in that it utilizes means for moving a coated member along a predetermined path through a mass of molten lead. The apparatus further includes means for circulating the molten lead to maintain substantially uniform temperature distribution throughout as well as to facilitate the separation of the coating from the cable since the circulation provides a resisting force which tends to strip the coating from the cable. The apparatus may also have means for imparting vibratory motion or shock forces to the molten lead mass. This feature facilitates the separation of the coating from a coated member because the vibratory motion creates a shock or impact on the coating which tends to strip the same from the member.

It is therefore the primary object of this invention to provide apparatus and a method for separating at least a pair of materials from each other when the materials are initially bound together as a unitary body wherein the body is moved along a predetermined path through a mass of molten lead to cause one of the materials to disintegrate or otherwise separate from the other material due to the heat of the lead mass so that the separated materials can be directed to respective locations in the lead mass and removed therefrom independently of each other.

Another object of this invention is to provide apparatus and a method for reclaiming lead from an elongated, leadcoated member wherein the member is moved along a path into and through a mass of molten lead so that the lead coating will itself become molten and will be separated from the member and will coalesce with the lead mass as the member is moved out of the same to a collection region.

A further object of this invention is to provide apparatus and a method for reclaiming lead from a leadcoated cable wherein the cable can remain in one piece rather than be cut up into segments and can be moved intact into, through and out of a mass of molten lead and thereafter be directed to a storage or collection area at which the cable can be wound upon a reel or otherwise be disposed so that it will be ready for immediate use without further processing or handling.

Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawings for an illustration of the apparatus for carrying out the method of the invention.

In the drawings:

FIG. 1 is a schematic view of the apparatus of the present invention;

FIG. 2 is a vertical section through and longitudinally of the tank of the apparatus;

FIG. 3 is a top plan view of the tank showing a number of coated members disposed in the tank;

FIG. 4 is a cross sectional view taken along line 44 of FIG 3;

FIG. 5 is a cross sectional view taken along line 5-5 of FIG. 3; and

FIG. 6 is an enlarged fragmentary cross sectional view of a carrier for moving the forward end of a coated member through the tank.

The apparatus for separating materials of this invention is broadly denoted by the numeral 10 and includes a tank 12 having a mass 14 of molten lead therewithin and provided with heater means 16 for heating the tank and thereby the lead mass to keep the latter in a molten condition. The apparatus is adapted for separating materials from one or more bodies or members 18 which are comprised of at least two different materials bound or secured together, at least one of which is responsive in a different manner to heat than the other. For instance, one of the materials can be lead which will become molten upon contact with molten lead mass. As another example, one of the materials could be paper or rubber insulation which will disintegrate or otherwise change its physical form when it contacts the molten lead mass.

For purposes of illustration only, each member 18 is elongated and initially mounted on a supply drum or reel 20 supported in any suitable manner adjacent to the entrance end 34 of tank 12. The drum may be rotated in any suitable manner, such as by motor 22 coupled by a belt and pulley assembly 24 to the central shaft of the drum. Similarly, a rotatable, take-up drum or reel 26 is mounted adjacent to the end of tank 12 and is coupled 4 to a motor 28 for receiving and storing one of the materials separated from member 18.

Further, for purposes of illustration only, members 18 will be described herein as lead-coated cables wherein each member is comprised of a central cable 30 of any suitable material, such as copper or the like, and an outer lead coating 32. A layer of insulating material such as paper, plastic, rubber or the like may be disposed between cable 30 and coating 32 and thereby will comprise a third material capable of being separated from the cable and the lead coating. When the apparatus is used with cables of this type, the purpose will be to strip the lead coating from the cables, to cause the coating to coalesce with the lead mass, and to wind the cables on drum 26 whereupon the cables can then be recoated with other materials or used in some other manner without a coating.

Entrance and exit ends 34 and 36 of tank 12 are gently sloping to accommodate relatively stiff members 18 and cables 30, respectively and to prevent splashing of the molten lead. Sides 38 and 40 of tank 12 (FIGS. 4 and 5) are steeper than ends 34 and 36 but do have some slope so that heater means 16 can apply heat to the sides of the tank in a manner to be described.

Tank 12 can be mounted in any suitable manner. Preferably, it will be suspended by concrete or other pedestals 42 at its four corners in the manner shown in FIG. 4. The tank supports could be provided by suitable legs as shown in FIG. 1. The tank can be formed from steel or the like in any suitable manner but preferably it will be cast as an open-top, imperforate body to eliminate holes through the tank and thereby avoid seal problems. Any connections which are to be made to the tank can be done by welding.

Spaced bearing rods 44 are provided adjacent to entrance end 34 and the spaced bearing rods 46 are provided at exit end 36. Rods 44 and 46 are transverse to the paths or travel of members 18, and maintain the latter out of contact with the end walls of the tank. A pair of spaced guide rods 48 and 50 are secured to and span the distance between sides 38 and 40 as shown in FIGS. 2, 3, 4 and 5. Also, a barrier plate 52 adjacent to exit end 36 is secured to and spans the distance between side walls 38 and 40. Plate 52 is spaced above the bottom 54 of tank 12 and projects upwardly from the upper surface 56 of lead mass 14. The purpose of plate 52 is to confine the slag or dross of the lead mass to the main body of the tank as cables 30 emerge from the lead mass at the exit end 36. Thus, the dross is not carried out of tank 12 with the cables.

Agitator means broadly denoted by the numeral 58 is disposed in tank 12 to agitate the lead mass by causing a circulation of the molten lead, whereby the temperature of the lead in the mass will be kept substantially uniform throughout the entire mass itself. To this end, agitator means 58 includes a number of spaced paddle wheels 60 which extend transversely of members 18. Since the tank is to be preferably made without any holes therein, it is desirable to provide structure externally of lead mass 14 to support the paddle wheels. While the paddle wheels can be supported in any desired manner, one way of supporting them is shown in FIGS. 2, 3 and 5 wherein a pair of side plates 62 suspended by lateral support members 64 have their lower margins extending into the lead mass. Support members 64 are, in turn, secured to structure adjacent to the sides of the tank and externally thereof. If desired, support members 64 can be made to be raised and lowered relative to the external support structure so that paddle wheels 60 can be moved into and out of the lead mass for cleaning or replacement purposes, if such is deemed necessary or desirable.

Each paddle wheel is secured by bearings 66 at its opposed ends to plates 62 and has a semicircular hood or cover 68 above the same (FIG. 2). Each hood 68 isolates the lead mass above the respective paddle wheel from the agitating action thereof so that there will be no turbulence at the upper region of the lead mass as the lead circulates in the tank.

Means for rotating the paddle wheels includes a motor 70 coupled by a bevel gear and linkage assembly 72 to each paddle wheel 60 respectively so that the paddle Wheels rotate together, at essentially the same speed, and in the same direction. Preferably, the paddle wheels will be rotated in a clockwise sense when viewing FIG. 2, so that the circulation will serve the dual purpose of keeping the temperature distribution in the lead mass substantially uniform and to facilitate the separation of coating 32 from each cable 30. Since, in practice, the members 18 will be moving to the right when viewing FIG. '2, movement of the lead mass adjacent to the members in the opposite direction will produce a force tending to strip the coating from the cable.

Means is provided to direct the leading end of each member through the mass of molten lead to initiate the material separation process. To this end, a carrier 74 is provided for each member 18 respectively. Each carrier 74 (FIG. '6) includes a movable element 76 disposed between a pair of relatively convergent retainer walls 78 extending longitudinally of tank 12 between ends 34 and 36. Retainer walls 78 are rigidily secured in any suitable manner to bottom 54 of tank 12. Each side of element 76 is recessed to define edges 80 which are in sliding, line contact with the inner surface of respective retaining walls 78 to minimize friction effects. Each element 76 is preferably formed from a material having a smaller density than lead so that the element will tend to rise in the lead mass. In this way, edges 80 will normally contact walls 78.

Each element 76 has a stem 82 extending upwardly therefrom, the stem having a suitable clamp or other fastener 84 on the upper end of the stem to clamp the leading end of cable 30 to the stem. As shown in FIG. 6 clamp 84 has a saddle 86 which receives the cable and which can serve as a guide when element 76 is adjacent to exit end 36.

Cables 88 and 90 are secured to the downstream and upstream faces, respectively of each element 76 (FIG. 3) and are of sufficient length to allow the element 76 to traverse the distance between entrance and exit ends 34 and 36 by manual or automatic control of cables 88 and 90. For automatic control, these cables may be connected to a suitable power drive unit at each end of the tank.

Heater means 1-6 may be of any suitable construction, but for purposes of illustration, it includes a number of burners 92 located below tank 12 and distributed to provide for substantially uniform heat application to lead mass 14. Some of these burners are adjacent to sides 38 and 40 (FIGS. 4 and 5) to more assuredly achieve this end. Burners 92 are connected to respective manifolds 94 which are spaced apart and extend transversely to the path of travel of members 18. Manifolds 94 are connected to a common pipe 96 which supplies a combustible fuel to the manifolds and thereby to burners 92. Any suitable means for actuating the burners may be provided.

A valve 98 coupled to tank 12 at any suitable location is used to drain molten lead therefrom. The valve may be manually actuated or operated through a float switch responsive to the level of the molten lead in the tank.

One or more vibrators 100 are preferably provided to cause a vibratory motion to be imparted to the tank and thereby to lead mass 14. Such vibratory motion enhances the separation of coatings 32 from cables 30, especially if the motion is in the form of a shock wave which travels through the molten lead. Any suitable control can be used for actuating vibrators, two of which are shown in FIG. 5 on side walls 38 and 40.

The method of the present invention is carried out by first providing the lead mass in tank 12 and heating the lead until it becomes molten. Paddle wheels 60 are then caused to rotate to circulate the molten lead whereby the temperature distribution throughout lead mass 14 will be substantially uniform. Members 18 will preferably be supplied on respective drums 20 but a single drum could be used, if desired.

Elements 76 will initially be adjacent to entrance end 34 with clamps 84 out of the lead mass. To connect members 18 to respective elements 76, each coating 32 is stripped back from the leading end of the member to expose the end of cable 30. This cable end is then attached to the corresponding clamp and the member is then ready to be pulled through the mass of molten lead by applying a pulling force on the corresponding cable 88.

Cables 88 are then pulled to the right when viewing FIGS. 2 and 3 whereupon the members 18 are pulled into and through the lead mass. The heat of the lead mass causes coatings 32 to become molten and eventually to become separated from the cables 30 and to coalesce with lead mass 14. While the movement of members 18 through lead mass 14 can be continuous or intermittent, the members will be in the molten lead for a time sufiicient to assure complete separation of coatings 32 from cables 30. Also, the speed of movement of members 18 through the molten lead, if such movement is continuous, will depend upon the length of tank 12 so that the necessary heating of coatings 32 will be assured.

The removal of coatings 32 from cables 30 is shown in FIGS. 2 and 3 wherein coatings 30 are reduced in thickness progressively as exit end 36 is approached. This may not be the actual way in which the separation occurs in practice, but it merely serves to illustrate the end result which is complete removal of coatings 32 from cables 30.

As soon as elements 76 reach exit end 36, clamps 84 will emerge from the lead mass and other clamp structure can be attached to the leading ends of cables 30 so as to pull the cables out of the tank and onto respective drums 26 or onto a single drum, if desired. Drums 26 will be rotated by motor 28. As the cables 30 continue to move out of the lead mass, saddles 86 of clamps 84 may serve as guides for the cables while elements 76 remain essentially stationary adjacent to exit end 36.

Paddle wheels 60 enhance the separation of coatings 32 from cables 30 due to the stripping action of the force represented by the circulation produced by the rotation of the paddle wheels. Since hoods 68 minimize turbulence, there -will be substantially no tendency for the lead mass to splash and to thereby pass as vapor into the atmosphere above the lead mass. Moreover, the sloping walls at the exit ends of the tank minimize splashing as do the sloping side walls 38 and 40.

Vibrators are operated either intermittently or continuously to impart vibratory motion to the side walls 38 and 40 whereby lead mass 14 will also be subjected to vibration. This vibratory motion will preferably be in the nature fo a shock wave through the lead mass to enhance the separation of coatings 32 from cables 30.

If insulation is provided between cables 30 and coatings 32, the insulation Will also be separated from cable 30 by being disintegrated since it will usually burn or otherwise change state by the heat of the molten lead of mass 14. The burned remnants of the insulation will rapidly rise to the top of the lead mass due to the wide difference in densities therebetween.

As cables 30 emerge from the lead mass, plate 52 will confine essentially all of the dross to the main body of the lead mass. Thus, the cables will be essentially clean, i.e. will have both insulation and lead coating removed therefrom. There is, therefore, no further processing necessary to reclaim the cables and they will be immediately ready for further use. Periodically, the lead mass will be drained from tank 12 by the actuation of valve 98 and the 7 drained lead will be substantially pure in that all impurities will have risen to the top of the lead mass due to differences in densities.

The present method assures separation of different materials because each cable 30, which is one material, is moved toward one end of tank 12 while the lead coating, which is another material, is moved to another location of the main body of the lead mass. If a third material is involved, such as insulation, it will be moved to a third location, mainly the upper surface of the lead mass. Additional structure to facilitate separation can be employed if desired. For instance, if a metallic coating on cables 30 is to be separated therefrom, the coating may not only be caused to rise to the surface of the lead mass due to density variations, but it can also be directed to specific areas by magnetic or other attractive forces. Since lead is generally more dense than many materials, especially metals and plastics, it serves as an extremely practical vehicle for effecting separation of different materials.

While the present invention has been illustrated and described with respect to elongated members, it is clear that members 18 do not have to have lengths sufiicient to span the distance between the ends of the tank. For instance, a relatively short member 18 can be drawn through the molten mass of lead by an element 76 Whereupon the heat of the lead mass will effect the desired separation.

Other carriers can be used if desired. For instance, an endless belt conveyor or conveyors can be used instead of carriers 74.

While one embodiment of this invention has been shown and described, it will be apparent that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

What is claimed is:

1. A method of removing the lead coating from a leadcoated cable member comprising: preparing a mass of molten lead; maintaining the temperature of the lead at a value suflicient to maintain the lead in molten condition; directing the cable member through the mass along a path and for a time suificient to heat the coating to said temperature value to cause the coating to melt and thereby to effect separation of the lead coating from the cable member; imparting vibratory motion to the lead mass to assist the removal of the lead coating from the cable member; and moving the cable member out of the lead mass.

2. A method as set forth in claim 1 wherein said maintaining step includes agitating the lead mass to assure uniform temperature distribution throughout.

3. A method as set forth in claim 1 wherein is provided the step of imparting vibratory motion to the lead mass to facilitate the removal of the lead coating from the cable.

4. A method as set forth in claim 1 wherein said maintaining step includes circulating the lead in said lead mass to assure uniform temperature distribution throughout.

5. A method as set forth in claim 1 wherein is provided the steps of maintaining the dross of said molten lead in said lead mass as the cable member is moved out of the same, winding the cable member on a reel after it has moved out of said lead mass, and draining excess lead from said lead mass.

6. A method of reclaiming lead from a lead-coated cable comprising: preparing a mass of molten lead; heating said lead mass to maintain the same in a molten condition; directing said cable into said lead mass at one extremity thereof; advancing the cable through said lead mass along a path and for a time sufficient to cause the lead coating to become molten and to be separated from the cable; imparting vibratory motion to said lead mass to facilitate the separation of the lead coating from the cable; circulating the molten lead in said lead mass to assure a substantially uniform temperature distribution throughout; removing the cable from said lead mass at another extremity thereof; and maintaining the dross of said molten lead in said lead mass as the cable is removed therefrom.

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HENRY W. TARRING II, Primary Examiner US. 01. X.R. 29-424; 7s 77; 1176 

